The question that no tapestry techniques book I’ve ever seen (including mine) addresses is how much weft yarn do you need for a tapestry. Frustrating, right? If you don’t have a yarn stash, how do you know how much to buy?

If you owned a yarn store, you might just grab an extra skein if you ran out and not worry about it. But most of us do not own our own endless yarn supply. We want to make sure we won’t run short but we also don’t want piles of a color we may never use again.

Tapestry weaving has a different structure than other weaving and so the amount of yarn you need is a bit different that if you were weaving a scarf on a rigid heddle loom. However, some of the methods of estimating amounts are similar. There are several approaches you could take to figure out how much weft yarn you need. Warp needs are easier to calculate and I’ll address that at the end of the post.

Three ways to calculate the amount of weft yarn you’ll need

Weave a swatch and count picks per inch (or use a completed weaving)
Weave a swatch and unravel it, measuring the weft (this one is for the seriously committed)
Weigh the swatch/weaving and use the manufacturer’s yarn weights for an estimate of yardage

Let’s look at each of those ideas. (And if the math quickly makes your head spin, scan down a ways for a simple ball-park number that involves no math at all.)

#1 Weave a swatch and count picks per inch. You could absolutely do this on a tapestry you’ve finished. Just make sure you’re using the same yarn at the same number of strands throughout the weaving.

In the photo below, look for the little rice-shapes that each weft makes as it goes over the warp. Count up one warp rib how many of these shapes are stacked on top of each other. Count the number in an inch and you have half of the picks-per-inch (ppi) which is a standard term for weavers of fabric but isn’t one we talk about as much in tapestry. If you are having difficulty seeing each little rice-shaped bead of weft, you might be beating your tapestry a tad too hard!*

Because of the structure of tapestry and how we just counted, we have to double the number you counted along just one warp rib. If you think about how tapestry works, it takes two picks to make a solid line, so if we only count the beads that are stacking up one warp rib, we are missing half of the weft in the tapestry. What we really want to know is sequences per inch. In the formula below we will take the number you counted climbing one warp rib and multiply by two to take into account all of the weft in the sampler.^

Counting picks per inch on a woven sample.

Once you’ve counted the sequences in an inch, you can do some simple math to find the length of weft needed to cover that area. Measure the width and length of your sample carefully. The trouble with this method is the difficult-to-quantify thing often called take-up. Each time the weft goes over and then under a warp thread, extra weft is needed. This is why we bubble our weft as we lay it in. Because the warps don’t bend much in tapestry, all of that take-up is happening in the weft. And it can be considerably more than you think! If you want to figure out how much this take-up is, you could weave a small swatch and apply this #1 technique and then after noting the numbers, do #2 where you actually unravel the weaving and measure the weft. That would help you figure out what take-up is for your particular combination of warp, weft, and sett.

To calculate the yards needed, use the formula indicated below. You’ll take the picks per inch you counted up just one warp rib which you will double in that first step (PPI), multiply it by the length of your sample in inches and then the width of your sample in inches. Then multiple that number by 1.25. This gives you a 25% additional amount to account for take-up. Take-up will vary depending on the materials you’re using and the sett. Divide this number by 36 to convert from inches to yards. The result is the number of yards needed to weave that sample.

Whatever it is, the way you tell your story online can make all the difference.

This calculation does not take into account all the tails that were cut off when I wove this sample! Some tapestry designs have lots of tails which add a considerable number of inches to the total. Others don’t have many tails and the number would be less. You’ll need to estimate the amounts of yarn you cut off or isn’t accounted for in this method.

In my example, my ppi was 15 x 2 = 30, my sample length was 12.5 inches, my width was 3 inches, so my number of yards needed was 39.06 yards without considering the tails.

#2 Weave a swatch and unravel it, measuring the weft. This is a little more work, but it might give you a somewhat more accurate result. Unless you need a really accurate number, I don’t think the work involved in this method is worth it especially if you’re only weaving smallish tapestries.

Here it is: Weave a swatch that is 2-3 inches square. Make sure to measure how wide that weaving was and definitely write down the sett. Then if it were me, I’d just cut the warps quite close to the weft and unravel the whole thing onto a ball winder. If you have a yardage counter you can measure it that way or you can use a tape measure a yard at a time to see how much weft went into it. To check yourself against other methods you could even save the warp you pulled out and weigh it using both this method and the one below to check yourself. Try not to stretch the yarn as you measure it. Take-up is automatically considered in this method.

#3 Weigh the swatch and (maybe) subtract the weight of the warp. This is the simplest method. If you have a weaving done in the sett and materials you usually use, especially if you haven’t added other materials like tags and twill tape for the finishing, you can weigh it to help you estimate how much weft is in it. It is even better if you weigh it before you cut any tails off. Of course the warp is included in this weight and you can estimate the weight of the warp and subtract this from the weight of the sample. I usually just use the warp weight as my percentage of error. But if you want to figure out the warp weight, you could do that either by the manufacturer’s weight and length or by winding off a known amount of warp and weighing it.

Start by weighing your sample.

In this case I have just over an ounce of material in my sample.

The yarn I used for this sample was Harrisville Koehler singles. This yarn is noted by the manufacturer to be 2700 yards per pound. I used four strands of this yarn, though that doesn’t actually matter if we’re strictly looking at amount needed. By that I mean that if you know that a sampler of X size uses an ounce of yarn, I can multiply or divide that to know how much of this yarn I need to order for any larger or smaller tapestry.

This particular sample is approximately 1/4 of a square foot. A measurement that is often used for tapestries is the square foot (or perhaps centimeter or meter square). I have 1.01 oz of material in this sample. Multiply that by 4 and I get approximately 4 ounces per square foot. This includes the warp and does NOT include all the tails I cut off. But it is a good ball-park figure for how much weft I would need for a square foot of tapestry using this particular yarn.

I can connect that to the yarn specifically by comparing the weight needed to weave a particular area with the yards per pound. In this case there are 2700 yards per pound. My sampler is 1/16th of a pound (there are 16 ounces in a pound, my sampler is 1 ounce). 2700 / 16 = 168.75 yards

Remember that this includes the warp. 12 yards of the 12/9 cotton seine twine warp which is about what is included in this sampler only weighs 0.18 oz. This is a significant amount that comes close to 20% of the weight of the sample. This is why I tend to just use the warp weight as the margin of error instead of subtracting it and then adding another margin of error.

The number of yards figured out here, about 170, is a very different from the answer I got in #1, or is it? We have one more thing to consider here. In this sampler, I was using FOUR strands of Koehler singles together. So total yardage might have been 170 yards, but I need to divide that number by 4 to get the yardage of the bundle which is what we were counting in #1. 170 / 4 = 42.5. This comes pleasingly close to the answer I got by measuring the sampler and counting the picks per inch.

Don’t want to do any math? Use this number.

If you struggled with the math, there is a ballpark figure you can use that seems to be generally accurate for tapestries woven at about 8 epi. Keep in mind that some yarns are a fair bit heavier per yard due to the materials and if you’re weaving at different setts, this won’t hold.

In general, you’ll likely need about 100g or one skein of yarn to cover a square foot of tapestry.

This number matches almost exactly with the calculations I did for #1 and #3 above.

If you just use this figure to purchase your yarn, I’d buy a healthy percentage over just to be safe. If you’re a betting person, buy 10% more. If you really don’t want to run out, get 20% more. You can always use the leftovers for samples or a small tapestry.

How much of each color do I need?

Once you have a ballpark number with one of the above methods, you’ll need to estimate how much of each color you need. I suppose there is some image-based way to do this with a graphics program, but heavens I wouldn’t take the time. I just give the cartoon a good eyeball and estimate. Have a large area of one color? About how much of the tapestry uses that color? Half? Then get 50% of your yarn amount in that color. If you have lots of smaller amounts that are less than you’ll need from the yarn put-up you’re buying, then you’re okay. Just buy one skein of each of those colors. It is the larger amounts that you need to make sure to get enough of. Colors don’t always match if you buy the same one later if it came from a different dye lot, though if you’re using a yarn with multiple strands and you can mix the two dye lots, it is unlikely you’d notice the difference.

Remember to make sure to have enough yarn for the largest areas in your design. Often we have plenty of smaller bits for the details but can run out on a large single-colored background.

The Rebecca Method

To be perfectly honest, I don’t do any of these things. A small subset of you will be able to adopt my method. I dye my own yarn and I just dye a lot of the colors I want. It means I have a lot extra, but I use that for smaller projects or I give it away or sell it. This is not an efficient way to do it, but it works best for me in part because I either get a discount on the base yarn or, in the case of Harrisville Koehler singles, they have kept the price of the base yarn incredibly low for everyone. I also end up doing this because if I’m dyeing really light colors, I often need to dye more yarn than I need due to the way the dye formulas work.**

I will warn you that over the course of a decade, this leads to a fairly large problem with yarn storage, especially after a year of not holding in-person workshops where I off-loaded a lot of extra yarn on my students!

Keeping a palette of colors on hand

You can also be that person who stocks a certain palette of colors. If you use commercially dyed yarns, you can just keep the colors you like in stock on your shelves, replenishing as you run low. It is possible the dye lots won’t match, but if you’re bundling yarns in strands, it is unlikely to make any difference.

Examples of warp. 2-ply and 1-ply wool warps back left. The other three are cotton seine twine.

How much warp do I need?

Calculating warp amounts is a bit easier than weft because it is based on the loom you’re using and how many warp ends are in an inch.

How much warp you need depends on the loom you’re using. If you have a simple frame tapestry loom with pegs or slots, measure the height of the loom, add some for however much warp goes around the peg and any doubled selvedge strands, and multiply by the ends per inch and number of inches. You’ll get a pretty accurate measurement of how much warp you need for that project.

Height of the loom in inches + 10% or so for wrapping pegs (just add an inch to your height number) x epi x # inches wide / 36 = yards of warp.

Calculating needed warp for a simple peg or slot loom involves multiplying the height of the loom by the number of warp ends.

If you are using a floor loom, there are many calculators to figure out how much warp you need. HERE is one from Schacht. (Note, for tapestry there isn’t really any warp take-up. The take-up is mostly in the weft.)

If you’re using a table-top tapestry loom, you can use the same sort of calculation as you’d use for a peg loom but remember that the warp goes all the way around the loom so essentially the warp is twice as long as the loom is high.

Length of one warp x epi x # of inches wide / 36 = yards of warp.

Calculating the amount of warp for a continuously warped loom (Mirrix, Schacht Arras, various pipe looms) involves multiplying the distance AROUND the loom by the number of warp ends. The exception to that is a pipe loom warped in a method that pulls two layers of warp together.

Tapestry weaving isn’t as predictable as some of us might like it to be. Even with all of these measurements, we can run out of yarn. We might have been extra generous with our bubbling when we wove the tapestry or we might have steamed the sample we measured from especially hard. Measurements are just guidelines, so always remember to add a percentage of error if you need to be absolutely sure you won’t run out. Also keep in mind that the weights and lengths that the yarn company says is in a particular put-up of yarn might not be entirely accurate. Manufacturers are not measuring the length of yarn that goes into each skein. They’re using measurements they’ve set their equipment to and coming close to what the ball band says. Leave yourself some extra so you don’t run out.

What scale should you use if you’re using a method that involves weighing yarn? If you have a postage scale or a kitchen scale that weighs in tenths of an ounce, that is probably close enough. If you have a scale that weighs tenths or hundredths of a gram, perhaps for dyeing, that will give you a more accurate measurement, but for our purposes probably isn’t necessary. Remember there are 16 ounces in a pound and in the USA, most of our scales are in pounds/ounces. Some scales have a mode for grams which might be useful because yarn is often sold in gram amounts. 3.5 ounces is about equal to 100 grams. So if you have a skein that is labeled 100 grams (or weighs such), you have about 3.5 ounces of yarn. (Just google “grams to ounces” to convert for any amount. Units matter! Make sure that you’re comparing grams to grams and not grams to ounces. They’re different systems.)

Do you have a system for figuring out how much weft yarn you need for a tapestry? Let us know in the comments!

*That, or like me, you now need magnification to see small things at close distances. Thanks presbyopia.

^A weaver of balanced plain weave or functional fabric can usually see each pick as it travels across the weaving because the warp is also showing. In tapestry, the warp is not showing and we can’t forget that on the front we’re only seeing half of the weft, the other half of it is on the back. Thus we need to count sequences and not picks.

**And because I am lazy and I’d rather just dye twice the amount of that super light yellow yarn than take the time to make a dye solution that contains less dye. Light colors are hard to get right!

How much yarn do you need for a tapestry?